In the art of recovery of liquid and gaseous hydrocarbon fuels from wells, it is well known that a well often may not evolve enough natural pressure to drive the oil or gas to the well head at rates suitable for economic production. For example, low pressure gas wells can and do produce economically for long periods of time, but may become blocked by ground liquids seeping into the well bore. Even though the well may evolve sufficient pressure and volumes of gas to percolate the gas through the liquid blockage, the production rate of the well will nevertheless be diminished by the blockage. If the well cannot evolve sufficient pressure to percolate the gas through the liquid blockage at production rates, external apparatus is often used to clear the liquid blockage.
In low pressure oil wells, the evolution of natural pressure typically may be insufficient to drive the oil to the surface. One pound of gas pressure will support a column of oil about 2 1/2 feet high. Therefore, the natural production capability of an oil well is a function of both natural well pressure and well depth. For oil wells with limited or negligible natural production capacity, such external means as pumps or the application of compressed air to the well are commonly utilized to facilitate production.
Many such low pressure oil and gas wells have sufficient pressure to lift a column of liquid through a limited distance and the applicant herein is aware of existing concepts for the lifting of liquids in well bores by natural well pressure which it utilized to lift a column or slug of liquid through a succession of adjacent, vertically extending sections of the well bore.